Fix path.toUri for relative paths.

test/posix_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library path.test.posix_test;
 
 import 'package:unittest/unittest.dart';
 import 'package:path/path.dart' as path;
 
 import 'utils.dart';
@@ skipping 481 matching lines @@
     });
 
     test('with a string', () {
       expect(context.fromUri('file:///path/to/foo'), '/path/to/foo');
     });
   });
 
   test('toUri', () {
     expect(context.toUri('/path/to/foo'), Uri.parse('file:///path/to/foo'));
     expect(context.toUri('/path/to/foo/'), Uri.parse('file:///path/to/foo/'));
+    expect(context.toUri('path/to/foo/'), Uri.parse('path/to/foo/'));
     expect(context.toUri('/'), Uri.parse('file:///'));
     expect(context.toUri('foo/bar'), Uri.parse('foo/bar'));
     expect(context.toUri('/path/to/foo#bar'),
         Uri.parse('file:///path/to/foo%23bar'));
     expect(context.toUri(r'/_{_}_`_^_ _"_%_'),
         Uri.parse('file:///_%7B_%7D_%60_%5E_%20_%22_%25_'));
     expect(context.toUri(r'_{_}_`_^_ _"_%_'),
         Uri.parse('_%7B_%7D_%60_%5E_%20_%22_%25_'));
   });
 
@@ skipping 16 matching lines @@
 
     test('with a root-relative URI', () {
       expect(context.prettyUri('/a/b'), '/a/b');
     });
 
     test('with a Uri object', () {
       expect(context.prettyUri(Uri.parse('a/b')), 'a/b');
     });
   });
 }